In commercial aircraft it is becoming increasingly common to offer reclining seat units for first-class cabin areas, which reclining seat units on account of their medium-height partition walls are to provide an improved private sphere and the opportunity to relax. Such seat units, for example known from DE 195 44 754, comprise a shell-like enclosure of the comfort seat that can be converted into a bed. Devices for entertaining and informing the passengers can be located in the walls of the enclosure, or said walls can serve to accommodate further elements such as lighting, a foldout table plate or similar. The longitudinal extension of such comfort seats has a particular dimension because the individual seat unit with the surrounding walls is an integral object of fixed length.
In passenger aircraft the available cabin length is predefined depending on the type of aircraft or on the class arrangement in the passenger cabin. The distance between doors is different from one design type to another design type so that the actual cabin sections between the doors of the fuselage are not identical. If the seat units are designed with fixed lengths, it can happen that unusable space remains or that a seat row might have to be done without.
Due to this limitation and the predefined fixed lengths of passenger seat units it can become necessary, in various aircraft types or cabin layouts, to install different types of seat units of different lengths. Initial purchase and keeping different seat types at the ready is thus expensive. Furthermore, delays in changing the seating arrangement can occur if the desired seat type happens not to be available. It is thus possible that the required flexibility and adaptability of airline-related class layouts and the use of a passenger seat unit for various aircraft types is difficult to achieve.